Up to now, various types of strengthening devices for the leg muscles have been proposed, including the device according to US patent application US-2008248934 in the name of the applicant of the present patent application. Such device comprises a body having a ground support surface and a work surface, which are articulated to each other such that they can be angularly and mutually moved around a horizontal (in use) rotation axis.
In use, the user applies pressure on the work surface, either directly or via interposition of a drum peddle, in order to cause its angular movement around the horizontal axis with respect to the support surface.
The compression force applied by the user, in use, has a horizontal component, however, which can cause horizontal slipping or movement of the device itself. Hence the user, after having carried out repeated compression and release steps of the work surface for a certain time period, must interrupt the training and correctly reposition the device under his own foot or under the pedal.